High power battery-powered system

ABSTRACT

An electrical combination, a motorized device system, a motor assembly, a battery pack, and operating methods. The combination may include an electrical device including a device housing, a load supported by the device housing, the load being operable to output at least about 1800 watts (W), and a device terminal electrically connected to the load; a battery pack including a pack housing, battery cells supported by the pack housing, the battery cells being electrically connected and having a nominal voltage of up to about 20 volts, and a pack terminal electrically connectable to the device terminal to transfer current between the battery pack and the electrical device; and a controller operable to control the transfer of current.

RELATED APPLICATIONS

The present application claims the benefit of co-pending U.S.Provisional Patent Application No. 62/536,807, filed Jul. 25, 2017, andU.S. Provisional Patent Application No. 62/570,828, filed Oct. 11, 2017,the entire contents of both of which are hereby incorporated byreference.

FIELD

The present invention relates to battery-powered devices and, moreparticularly to high power batteries and such devices.

SUMMARY

A high-powered electrical combination is schematically illustrated inFIG. 1A. The combination generally includes a battery power source, anelectrical device including a load (e.g., a motor, as illustrated),electrical interconnections between the power source and the load, andelectronics operable to control, for example, discharge of the powersource, operation of the load, etc.

The combination is incorporated into a motorized device (e.g., powertools, outdoor tools, other motorized devices, etc.) or a non-motorizeddevice having an associated output mechanism powered by the load (e.g.,a saw blade, a bit, a grinding wheel, a power supply, a lighting device,etc.). At least some of the devices incorporating the combination arehand-held devices (e.g., a device supportable by a user duringoperation), and, accordingly, the combination must fit withinlimitations (e.g., weight, volume/package size, etc.) of a hand-helddevice.

In the illustrated construction, the battery power source has a nominalvoltage of up to about 20 volts (V) (e.g., about 18 V to about 20 V).Also, the combination is operable to output high power (e.g., a peakpower of 1800 watts (W) to 2400 W or more (2.4 horsepower (hp) to 3.0 hpor more)). In order to achieve this peak power, a high current (e.g.,100 amps (A) or more) is discharged from the power source, through theinterconnections, through components of the electronics and to the load.Again, this high power output is achieved within limitations of ahand-held device.

In contrast, existing combinations for hand-held devices, with a nominalvoltage of 18 V to 20 V, are operable to output only between about 1000W to about 1400 W at a current of between about 50 A to 70 A. There aremany challenges evolving from performance of the existing technology tothat of the present invention.

One challenge is increasing the deliverable power of the battery powersource. Such an increase can be obtained by increasing the number ofcells in the battery, in series and/or in parallel. An increase in thecell form factor, with associated reduced impedance, will also increasethe available power. However, each of these solutions results in anincrease in the size and weight of the battery power source, contrary tothe limitations of the hand-held devices.

Another challenge is effectively exploiting at the load (e.g., themotor) the power provided by the battery power source. An increase inmotor size (e.g., diameter) will result in increased power output. Suchan increase again conflicts with the limitations of hand-held devices.To maximize increased deliverable power from the battery power source tothe load, impedance and losses in the system must be reduced.

Increased deliverable power from the battery power source and/orincreased power output from the load require additional electronics tocontrol such discharge, operation, etc. Further, the increased powerfrom an 18 V to 20 V battery power source requires an increased currentwhich generates heat. Operation must be controlled and/or coolingstructure provided to manage the increased current and heat.

As mentioned above, existing devices operate at a peak current of 50 Ato 70 A. Again, to achieve the high output power in the presentcombination with a 18 V to 20 V battery power source, the peak currentis at least about 100 A. Existing interconnections (e.g., terminals,switches, conductors, etc.) are not designed to handle the increasedcurrent/heat. Operation must be controlled and/or cooling structureprovided to manage the increased current and heat.

However, overcoming these challenges raises others. For example,increased power from the power source and output by the load couldpossibly be achieved by adding more and/or larger components—more andlarger battery cells, a larger motor, thicker terminals, biggerswitches, etc. As discussed above, each of these additions, however,conflicts with the limitations imposed by the device being hand-held bymaking the combination heavier, larger, etc.

As another example, the high power battery power source may be used withexisting electrical devices, and these devices are not constructed tohandle the available high power from the power source. As mentionedabove, to handle with increased current, improvements have been made tothe interconnections and to the electronics. The existing devices do notinclude such improved components and could be damaged by the increasedpower, current, heat, etc.

As yet another example, in existing electrical devices, due torelatively-higher impedance in the system (battery, interconnections,electronics, motor), the stall current of the motor was lower than themaximum current of components (e.g., switches, field-effect transistors(FETs), etc.) in the system. Accordingly, in existing devices, the motorwould stall before the components were subjected to their maximumcurrent. With the reduced impedance in the present combination, thestall current now exceeds these maximum current values. In operation,the current can now exceed the component current thresholds beforestalling.

In one independent embodiment, an electrical combination may generallyinclude an electrical device, a battery pack and a controller. Theelectrical device may generally include a device housing, a loadsupported by the device housing, the load being operable to output atleast about 1800 watts (W) (about 2.4 horsepower (hp)), and a deviceterminal electrically connected to the load. The battery pack mayinclude a pack housing, battery cells supported by the pack housing, thebattery cells being electrically connected and having a nominal voltageof up to about 20 volts, and a pack terminal electrically connectable tothe device terminal to transfer current between the battery pack and theelectrical device. The controller may be operable to control thetransfer of current. The load may be operable to output at least about2200 watts (W) (about 3 horsepower (hp)).

In some constructions, the load includes a motor including an outputshaft, the motor being operable to output at least about 1800 watts (W)(about 2.4 horsepower (hp)). In some constructions, the device includesa power tool, and the motor is operable to drive a tool member. Themotor may include a brushless direct current motor. The motor mayinclude a stator having a nominal outer diameter of between about 60millimeters (mm) and about 80 mm (e.g., about 70 mm).

In some constructions, the battery cells each have a diameter betweenabout 18 mm and about 21 mm and a length between about 65 mm and about71 mm (e.g., a diameter of about 21 mm and a length of about 71 mm). Thebattery pack may include up to 15 battery cells, and the battery cellsmay be arranged in sets of battery cells (e.g., five cells) connected inseries, the sets being connected in parallel.

The battery cells may be operable to output an operating dischargecurrent of between about 80 Amps (A) and about 110 A and to output apeak discharge current up to about 200 A. The battery cells may have acapacity of between about 3.0 Amp-hours (Ah) and 5.0 Ah.

In some constructions, the combination may also include a power circuitelectrically connected between the battery cells and the motor, thepower circuit including semi-conducting switches operable to applycurrent to the load. The load may include a brushless direct currentmotor, the switches being operable to apply current across the windings.A heat sink may be in heat transfer relationship with the switches andhave a thermal capacity of at least about 63 joule per Celsius (J/C).The heat sink may be intersected by a rotational axis of the rotor. Acombined length of the motor and the heat sink is up to about 84 mm.

In some constructions, the device may include a hand-held power tool.The pack housing may connectable to and supportable by the devicehousing such that the battery pack is supportable by the hand-held powertool.

In the combination, control electronics including the controller mayhave a volume of up to about 15,000 cubic millimeters (mm³) (e.g., about8750 mm³ (dimensions of about 50 mm by about 35 mm by about 5 mm)), themotor may have a volume of up to about 92,000 mm³, and the battery packmay have a volume of up to about 1,534,500 mm³. The control electronicsmay have a weight of up to about 19.6 grams (g), the power electronicsmay have a weight of up to about 94.1 grams (g), the motor may have aweight of up to about 1.89 lbs., and the battery pack may have a weightof up to about 3.5 lbs.

In another independent embodiment, a motorized device (e.g., a powertool) system may generally include a power tool, a battery pack, and acontroller. The power tool may include a tool housing, a motor supportedby the tool housing, the motor including an output shaft operable todrive a tool element, the motor being operable to output at least about1800 watts (W) (2.4 horsepower (hp)), and a tool terminal electricallyconnected to the load. The battery pack may include a pack housing,battery cells supported by the pack housing, the battery cells beingelectrically connected and having a nominal voltage of up to about 20volts, and a pack terminal electrically connectable to the tool terminalto transfer current between the battery pack and the power tool. Thecontroller may be operable to control the transfer of current.

In yet another independent embodiment, a method of operating an electricmotor may be provided. The method may generally include supplying afirst voltage signal at a first duty cycle to the motor; determiningwhether a current to be supplied to the motor exceeds a threshold; and,if the current to be supplied exceeds a threshold, supplying a secondvoltage signal at a second duty cycle to the motor, the second dutycycle being less than the first duty cycle.

The method may also include, after supplying a second voltage signal ata second duty cycle to the motor, determining whether a current to besupplied to the motor exceeds the threshold; and, if the current to besupplied exceeds the threshold, supplying a third voltage signal at athird duty cycle to the motor, the third duty cycle being less than thesecond duty cycle. The method may also include, after supplying a secondvoltage signal at a second duty cycle to the motor, determining whethera current to be supplied to the motor exceeds the threshold; and, if thecurrent to be supplied does not exceed the threshold, supplying thefirst voltage signal at the first duty cycle to the motor. Accordingly,the method may continuously vary the duty cycle to provide maximumdesired output current.

Supplying includes supplying a voltage signal through a switch, andwherein the current threshold is associated with the switch. Supplying avoltage signal through a switch includes supplying a voltage signalthrough a field-effect transistor (FET), the current threshold beingassociated with the FET.

In a further independent embodiment, a method of operating a motor maybe provided. A FET may be operable to supply current to the motor, and arelay may be operable to supply current to the FET. The method maygenerally include, in response to a signal to operate the motor,determining whether the FET is operational; and, if the FET isoperational, operating the relay to supply current through the FET tothe motor. In some constructions, a second FET may operable to supplycurrent to the motor, and the method may further include, beforeoperating the relay, in response to the signal to operate the motor,determining whether the second FET is operational.

The method may further include, if the FET is not operational, disablingoperation of the motor. Disabling may include temporarily disablingoperation of the motor. The method may include, after temporarilydisabling, determining whether the FET is operational; if the FET isoperational after temporarily disabling the motor, operating the relayto supply current through the FET to the motor; and/or, if the FET isnot operational after temporarily disabling the motor, permanentlydisabling the motor.

Determining may include turning on the FET. Determining may includesupplying a test signal to the FET, and monitoring an output of the FET.The signal may include a trigger signal.

In another independent aspect, a method of operating an electricalcombination may be provided. The electrical combination may include anelectrical device and a battery power source, the device including adevice terminal, the battery source including a plurality of cellshaving a voltage and a battery terminal connectable to the deviceterminal. The method may generally include connecting the plurality ofbattery cells to the battery terminal across a resistor to supplycurrent to the device, the resistor having a first resistance;determining whether a condition has occurred; and, after the conditionoccurs, connecting the plurality of battery cells to the batteryterminal through a switch, the switch having a second resistance lessthan the first resistance.

Determining may include determining whether a time period has elapsed.Determining whether a time period has elapsed may include determiningwhether a start-up time period has elapsed. Connecting through a switchmay include shorting the resistor with the switch. Connecting through aswitch may include connecting the plurality of battery cells to thebattery terminal through a FET.

In yet another independent aspect, a battery pack may generally includea housing; a plurality of cells supported by the housing and having avoltage; a battery terminal; an electrical circuit selectivelyconnecting the plurality of cells to the battery terminal to supply acurrent to an electrical device, the circuit including a resistor in afirst electrical path between the plurality of cells to the batteryterminal, the resistor having a first resistance, and a switch in asecond electrical path between the plurality of cells to the batteryterminal, the switch having a second resistance less than the firstresistance; and a controller operable to selectively connect theplurality of cells to the battery terminal across the resistor orthrough the switch.

The controller may be operable to control the switch to short theresistor. The controller may be operable to close the switch to shortthe resistor. The controller may be operable to control the switch aftera condition occurs. The controller may be operable to control the switchafter a time period has elapsed. The controller may be operable tocontrol the switch after a time period after start-up. The switch mayinclude a FET.

In a further independent aspect, an electrical combination may generallyinclude an electrical device, a battery pack, and an electrical circuit.The electrical device may include a device housing, a load supported bythe device housing, and a device terminal electrically connected to theload. The battery pack may include a pack housing, battery cellssupported by the pack housing, the battery cells being electricallyconnected, and a pack terminal electrically connectable to the deviceterminal to transfer current between the battery pack and the electricaldevice. The electrical circuit is between the battery cells and the loadand may include a discharge switch operable to selectively connect thebattery cells to the load, an operation switch operable to output anoperation signal, a controller operable to determine a condition of theelectrical device or the battery pack, and a logic portion operable toreceive a first input from the operation switch and a second input fromthe controller, the logic portion outputting a control signal to thedischarge switch based on the first input and the second input. Thedischarge switch may include an electromechanical relay or asemiconductor based solid state relay.

In another independent aspect, a battery pack may generally include ahousing including a support portion connectable to and supportable by anelectrical device, the support portion defining a channel operable toreceive a projection on the electrical device, the support portionincluding a plastic material molded to define the channel, and a metalmaterial molded in the plastic material, the metal material defining aC-shaped portion around the channel; a plurality of battery cellssupported by the housing; and a battery terminal electrically connectedto the plurality of battery cells and connectable to a terminal of theelectrical device.

In yet another independent aspect, an electric motor may generallyinclude a stator including a core defining a plurality of teeth, aplurality of coils disposed on respective stator teeth, and an end capproximate an end of the core, the end cap including a plurality of coilcontact plates molded in the end cap and a first terminal and a secondterminal separate from and connectable to the contact plates, thecontact plates short-circuiting opposite ones of the plurality of coils;and a rotor supported for rotation relative to the stator.

In a further independent aspect, an electric motor assembly maygenerally include a motor housing; a brushless electric motor supportedby the housing; and a printed circuit board (PCB) assembly connected tothe housing, the PCB assembly including a heat sink, a power PCB coupledto a first side of the heat sink, and a position sensor PCB coupled toan opposite second side of the heat sink and in facing relationship withthe motor. The position sensor PCB may include a plurality ofHall-effect sensors. The motor may include a rotor supporting a magnet,the Hall-effect sensors being operable to sense a position of themagnet.

Other independent aspects of the invention may become apparent byconsideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of an electrical combination including abattery assembly, an electronics assembly, and a motor assembly.

FIG. 1B is a block diagram of the electrical combination of FIG. 1A.

FIG. 2A illustrates a high power electrical system including varioushigh power electrical devices incorporating the high power electricalcombination of FIGS. 1A-1B.

FIG. 2B illustrates a system of existing electrical devices operable tobe powered by an existing battery pack or the high-power batteryassembly of FIGS. 1A-1B.

FIG. 3 is a perspective view of the motor assembly of the electricalcombination of FIGS. 1A-1B.

FIG. 4 is cross-sectional view of the motor assembly of FIG. 3, takenalong lines 4-4 of FIG. 3.

FIG. 5 is a cross-sectional view of the motor assembly of FIG. 3, takenalong lines 5-5 of FIG. 3.

FIG. 6A is a perspective exploded view of the motor assembly of FIG. 3.

FIG. 6B is a side exploded view of the motor assembly of FIG. 3.

FIG. 7 is a perspective view of the motor assembly of FIG. 3,illustrating a PCB assembly exploded from the remainder of the motorassembly.

FIG. 8 is a perspective view of the motor assembly of FIG. 3, withportions removed.

FIG. 9 is another perspective view of the motor assembly of FIG. 3, withportions removed.

FIG. 10 is an exploded view of the motor assembly of FIG. 3, withportions removed.

FIG. 11 is an exploded view of the motor assembly of FIG. 3, withportions removed.

FIG. 12 is a front view of a stator lamination.

FIG. 13 is a front view of a rotor lamination.

FIG. 14 is a perspective view of a stator end cap.

FIG. 15 is a perspective view of another stator end cap with coilcontact plates overmolded therein.

FIG. 16 is another perspective view of the stator end cap and coilcontact plates of FIG. 15, illustrating the stator end cap in atransparent state.

FIG. 17 is a perspective view of the coil contact plates of FIG. 15.

FIG. 18 is an enlarged partial perspective view of a stator end cap andcoil contact plate terminal according to an aspect of the invention.

FIG. 18A is a perspective view of a stator end cap with coil contactplates and attachable terminals, according to another aspect of theinvention, illustrating the stator end cap in a transparent state.

FIG. 18B is a manufacturing schematic for a coil contact plate accordingto an embodiment of the invention.

FIG. 18C is a manufacturing schematic for a coil contact plate andattachable terminals according to another embodiment of the invention.

FIG. 19 is a perspective view of a motor housing of the motor assemblyof FIG. 3.

FIG. 20 is another perspective view of the motor housing of FIG. 19.

FIG. 21 is a rear view of the motor housing of FIG. 19.

FIG. 22 is a front view of the motor housing of FIG. 19.

FIG. 23 is a rear view of a PCB assembly.

FIG. 24 is a front view of the PCB assembly of FIG. 23.

FIG. 25 is a perspective cross-sectional view of the PCB assembly ofFIG. 23, taken generally along lines 25-25 of FIG. 5.

FIG. 26 is a perspective view of a heat sink of the PCB assembly of FIG.23.

FIG. 27 is a perspective view of a fan of the motor assembly of FIG. 3.

FIG. 28 is a graph of current, efficiency, speed, and power as afunction of motor output torque for a high power tool system accordingto an embodiment of the invention.

FIG. 29 is a block diagram of an inverter bridge of the electricalcombination of FIGS. 1A-1B.

FIG. 30 is a flowchart of a method of checking FETs of the electricalcombination of FIGS. 1A-1B.

FIGS. 31A-31C illustrate timing diagrams of a voltage signal provided tothe inverter bridge of FIG. 29.

FIG. 32 is a flowchart of a method of hysteretic current control.

FIG. 33 is a top perspective view of the battery pack of FIG. 2A inaccordance with some embodiments.

FIG. 34 is a bottom perspective view of the battery pack of FIG. 33.

FIG. 35 is a top plan view of the battery pack of FIG. 33.

FIG. 36 is a bottom plan view of the battery pack of FIG. 33.

FIG. 37 is a front plan view of the battery pack of FIG. 33.

FIG. 38 is a rear plan view of the battery pack of FIG. 33.

FIG. 39 is a side plan view of the battery pack of FIG. 33.

FIG. 40 is a side plan view of the battery pack of FIG. 33.

FIG. 41 is an exploded view of the battery pack of FIG. 33.

FIG. 42 is a cross-sectional view of the battery pack of FIG. 33.

FIG. 43 is a top perspective view of the battery pack of FIG. 2A inaccordance with some embodiments.

FIG. 44 is a bottom perspective view of the battery pack of FIG. 43.

FIG. 45 is a top plan view of the battery pack of FIG. 43.

FIG. 46 is a bottom plan view of the battery pack of FIG. 43.

FIG. 47 is a front plan view of the battery pack of FIG. 43.

FIG. 48 is a rear plan view of the battery pack of FIG. 43.

FIG. 49 is a side plan view of the battery pack of FIG. 43.

FIG. 50 is a side plan view of the battery pack of FIG. 43.

FIG. 51 is an exploded view of the battery pack of FIG. 43.

FIG. 52 is a cross-sectional view of the battery pack of FIG. 43.

FIG. 53 is a top perspective view of the battery pack of FIG. 2A inaccordance with some embodiments.

FIG. 54 is a bottom perspective view of the battery pack of FIG. 53.

FIG. 55 is a top plan view of the battery pack of FIG. 53.

FIG. 56 is a bottom plan view of the battery pack of FIG. 53.

FIG. 57 is a front plan view of the battery pack of FIG. 53.

FIG. 58 is a rear plan view of the battery pack of FIG. 53.

FIG. 59 is a side plan view of the battery pack of FIG. 53.

FIG. 60 is a side plan view of the battery pack of FIG. 53.

FIG. 61 is an exploded view of the battery pack of FIG. 53.

FIG. 62 is a cross-sectional view of the battery pack of FIG. 53.

FIG. 63 is a block diagram of the battery pack of FIG. 2A.

FIGS. 64A-64C illustrate a switched resistance of the battery pack ofFIG. 2A.

FIG. 65 is a flowchart of a method of operating the battery pack of FIG.2A.

FIG. 66 is a block diagram of the battery pack of FIG. 33 according toone embodiment.

FIG. 67 is a flowchart of a method of switching cell strings of thebattery pack of FIG. 66.

FIG. 68 is a block diagram of the battery pack of FIG. 33 according toone embodiment.

FIG. 69 is a flowchart of a method of switching cell strings of thebattery pack of FIG. 68.

FIG. 70 is a block diagram of the battery pack of FIG. 33 according toone embodiment.

FIG. 71 is a flowchart of a method of switching cell strings of thebattery pack of FIG. 70.

FIGS. 72A-72B are perspective view of a switch of the battery pack ofFIG. 2A.

FIG. 73 is a block diagram of a connection between battery cells andbattery pack terminals of the battery pack of FIG. 2A.

FIG. 74 is a perspective view of a C-shaped channel for a supportportion of the battery pack of FIG. 2A.

FIG. 75 is a perspective view of the C-shaped channel in the supportportion of the battery pack of FIG. 2A.

FIG. 76 is a perspective view of a L-shaped channel for the battery packof FIG. 2B.

FIG. 77 is a block diagram of a connection between battery cells andbattery pack terminals of the battery pack of FIG. 2A.

FIG. 78 is a perspective view of the battery pack of FIG. 2Aillustrating a fuse connected to the negative terminals of batterycells.

FIG. 79 is a perspective view of the terminal block of a battery pack ofFIG. 2A.

FIG. 80 is a perspective view of a motor assembly in accordance withsome embodiments, illustrating a PCB assembly exploded from theremainder of the motor assembly.

FIG. 81 is a perspective view of the PCB assembly of FIG. 80, withportions removed.

FIG. 82 is a perspective view of an end cap in accordance with someembodiments, with coil contact plates overmolded therein.

FIG. 83 is a front view of the end cap and coil contact plates of FIG.82, illustrating the end cap in a transparent state.

FIG. 84 is perspective view of the coil contact plates of FIG. 82.

DETAILED DESCRIPTION

Before any independent embodiments of the disclosure are explained indetail, it is to be understood that the disclosure is not limited in itsapplication to the details of construction and the arrangement ofcomponents set forth in the following description or illustrated in theaccompanying drawings. The disclosure is capable of other independentembodiments and of being practiced or of being carried out in variousways. Also, it is to be understood that the phraseology and terminologyused herein are for the purpose of description and should not beregarded as limiting.

Use of “including” and “comprising” and variations thereof as usedherein is meant to encompass the items listed thereafter and equivalentsthereof as well as additional items. Use of “consisting of” andvariations thereof as used herein is meant to encompass only the itemslisted thereafter and equivalents thereof.

Relative terminology, such as, for example, “about”, “approximately”,“substantially”, etc., used in connection with a quantity or conditionwould be understood by those of ordinary skill to be inclusive of thestated value and has the meaning dictated by the context (for example,the term includes at least the degree of error associated with themeasurement of, tolerances (e.g., manufacturing, assembly, use, etc.)associated with the particular value, etc.). Such terminology shouldalso be considered as disclosing the range defined by the absolutevalues of the two endpoints. For example, the expression “from about 2to about 4” also discloses the range “from 2 to 4”. The relativeterminology may refer to plus or minus a percentage (e.g., 1%, 5%, 10%or more) of an indicated value.

Also, the functionality described herein as being performed by onecomponent may be performed by multiple components in a distributedmanner. Likewise, functionality performed by multiple components may beconsolidated and performed by a single component. Similarly, a componentdescribed as performing particular functionality may also performadditional functionality not described herein. For example, a device orstructure that is “configured” in a certain way is configured in atleast that way but may also be configured in ways that are not listed.

Furthermore, some embodiments described herein may include one or moreelectronic processors configured to perform the described functionalityby executing instructions stored in non-transitory, computer-readablemedium. Similarly, embodiments described herein may be implemented asnon-transitory, computer-readable medium storing instructions executableby one or more electronic processors to perform the describedfunctionality. As used in the present application, “non-transitorycomputer-readable medium” comprises all computer-readable media but doesnot consist of a transitory, propagating signal. Accordingly,non-transitory computer-readable medium may include, for example, a harddisk, a CD-ROM, an optical storage device, a magnetic storage device, aROM (Read Only Memory), a RAM (Random Access Memory), register memory, aprocessor cache, or any combination thereof.

Many of the modules and logical structures described are capable ofbeing implemented in software executed by a microprocessor or a similardevice or of being implemented in hardware using a variety of componentsincluding, for example, application specific integrated circuits(“ASICs”). Terms like “controller” and “module” may include or refer toboth hardware and/or software. Capitalized terms conform to commonpractices and help correlate the description with the coding examples,equations, and/or drawings. However, no specific meaning is implied orshould be inferred simply due to the use of capitalization. Thus, theclaims should not be limited to the specific examples or terminology orto any specific hardware or software implementation or combination ofsoftware or hardware.

FIGS. 1A-1B illustrate simplified block diagrams of an electricalcombination 10. The combination 10 includes a high power DC electricaldevice (e.g., power tool) system 14 that includes a power source (e.g.,a battery assembly 18), interconnects 20 (e.g., terminals, conductors,switches, etc.), an electronic assembly 22 (e.g., controls, switchingfield-effect transistors (FETs), trigger, etc.), a motor assembly 26. Asexplained in greater detail below, the high power DC tool system 14achieves a high power output with a DC power source within the packagingrestrictions (e.g., weight, volume, etc.) of a hand-held power tool.

FIG. 2A illustrates a high power electrical system 1000 includingvarious high power electrical devices incorporating the high powerelectrical combination 10. For example, the system 1000 includesmotorized power tools (e.g., a circular saw (e.g., a worm drive saw1010), a reciprocating saw 1014, a table saw 1018, a miter saw 1022, anangle grinder 1026, a SDS Max hammer 1030, a compressor 1034, a vacuum1038, etc.), outdoor tools (e.g., a chain saw 1042, a string trimmer, ahedge trimmer, a blower, a lawn mower, etc.), other motorized devices(e.g., vehicles, utility carts, etc.), etc. and non-motorized electricaldevices (e.g., a power supply, a light 1046, a testing device, an audiodevice 1050, etc.).

FIG. 2B illustrates a system 1100 of existing electrical devicesoperable to be powered by an existing battery pack 1104 or thehigh-power battery assembly 18, 18A, 18B. Likewise, the existingelectrical devices include various motorized power tools (e.g., acircular saw 1110, a reciprocating saw 1114, a grinder 1126, a vacuum1138, a drill 1154, a nailer 1158, an impact driver/wrench 1162, etc.),outdoor tools (e.g., a string trimmer 1166, a hedge trimmer, a blower1170, etc.), etc. and non-motorized electrical devices (e.g., an audiodevice 1150, a light 1174, a testing device, etc.).

With reference to FIGS. 3-7, a motor assembly 26 generally includes amotor housing 30, a motor 34 positioned within the motor housing 30, afan 38, a printed circuit board (PCB) assembly 42. The motor 34 includesa stator 46 and a rotor 50 positioned at least partially within thestator 46. A similar motor is described and illustrated in U.S.Provisional Patent Application No. 62/458,367, filed Feb. 13, 2017, theentire contents of which is hereby incorporated by reference.

With reference to FIGS. 3-7 and 19-22, the motor housing 30 includes acylindrical portion 54 at least partially housing the motor 34. Mountingbosses 58 are provided along the cylindrical portion 54 through whichfasteners 60 extend to interconnect the PCB assembly 42 to the motorhousing 26 and through which fasteners 61 extend to interconnect themain housing 26 with the stator 46. With reference to FIG. 6A, the motorhousing 30 also includes a hub portion 62 coaxial with the cylindricalportion 54 and axially spaced from the cylindrical portion 54, posts 66extending axially from a rear end 70 of the cylindrical portion 54, andradially extending spokes 74 interconnecting the hub portion 62 to thepost 66. Windows 78 are formed in a front end 82 of the cylindricalportion 54 radially outward from the fan 38.

With reference to FIGS. 5-6A, 7, and 19-22, the cylindrical portion 54of the motor housing 30 also includes radially inward-extending ribs 86extending the entire length of the cylindrical portion 54, with eachpair of adjacent ribs 86 defining a channel 90 therebetween. When themotor 34 is inserted into the motor housing 30, corresponding ribs 94 onthe motor 34 are slidably received within the respective channels 90defined in the cylindrical portion 54, thereby rotationally orientingthe motor 34 relative to the motor housing 30. In addition, the motorhousing 30 includes radially inward-extending support ribs 98 extendingthe entire length of the cylindrical portion 54, which contact andsupport the stator 46.

With particular reference to FIG. 5-11, the stator 46 includes aplurality of individual stator laminations 102 stacked together to forma stator core 106 (i.e., a stator stack). As mentioned above, the stator46 includes radially outward extending ribs 94 on an outercircumferential surface 110 extending the entire length of the statorcore 106. Adjacent ribs 94 define a concave channel 114, whichcorresponds to the channel 90 defined by the motor housing 30, throughwhich fasteners 61 extend. In addition, the stator 46 includes recesses118, the purposes of which is described below, extending parallel withand rotationally offset from the ribs 94.

With reference to FIG. 12, each stator lamination 102 includes a yoke122 (a.k.a., a rim, a back iron, etc.) having multiple radiallyoutwardly-extending protrusions 94′ (FIG. 12) collectively defining theribs 94 when the laminations 102 are stacked together. Each statorlamination 102 also includes recesses 118′ defined on the outer surfaceof the yoke 122 collectively defining the recesses 118 when thelaminations 102 are stacked together. The stator 46 also includesinwardly extending stator teeth 126 and slots 130 defined between eachpair of adjacent stator teeth 126 when the laminations 102 are stackedtogether. In the illustrated embodiment, the stator laminations 102include six stator teeth 126, defining six stator slots 130.

The stator 46 further includes stator windings 134 at least partiallypositioned within the slots 130. In the illustrated embodiment, thestator windings 134 include six coils 134A-134F connected in a threephase, parallel delta configuration. In alternative embodiments (notshown), the coils 134A-134F may be connected in alternativeconfigurations (e.g., series, delta, etc.). Insulating members 138 (FIG.10) are provided within each slot 130 to insulate that stator teeth 126from the stator windings 134. The stator windings 134 are wound aroundthe stator core 106 with a continuous (i.e., single wire) precisionwinding process that results in filling the slots 130 to a value of atleast 30%. In some embodiments, the slot fill may be at least 36%.

In some embodiments (i.e., a 45 millimeter (mm) stator stack length242), the stator windings 134 have a wire gauge of approximately 1.5 mm.In some embodiments, the delta, line-line resistance of the statorwindings 134 is within a range from approximately 3.82 mΩ toapproximately 5.18 mΩ. In other embodiments, the delta, line-lineresistance of the stator windings 134 is approximately 4.5 mΩ. Theparallel resistance of the stator windings 134 (i.e., the resistance oftwo coils in parallel) is within a range of approximately 6.3 mΩ toapproximately 7.7 mΩ. In some embodiments, the parallel resistance ofthe stator windings 134 is approximately 7.0 mΩ.

The stator 46 includes a rear end cap 142 adjacent a rear end 146 of thestator core 106 and a front end cap 150 adjacent a front end 154. Withreference to FIGS. 8-10 and 14-15, each end cap 142, 150 includes rimportions 158 and end cap teeth 162 extending radially inward from therim portions 158. The end cap teeth 162 include projections 166 thatsupport the respective stator coil windings 134. The stator windings 134are also guided between adjacent stator teeth 126 by flanges 170 formedon the rear end cap 142.

Each end cap 142, 150 additionally includes tabs 174 extendingtransversely from the rim portions 158, with each tab 174 including aradially inwardly extending projection 178 received in the correspondingrecesses 118 formed on the stator core 106 to rotationally align theeach end cap 142, 150 relative to the stator core 106. The rear end cap142 includes concave recesses 182 aligned with the channels 114 in thestator core 106 through which the fasteners 61 extend. Likewise, thefront end cap 150 includes concave recesses 186 aligned with thechannels 114 in the stator core 106.

With reference to FIGS. 15-17, the stator 46 includes coil contactplates 190 (also referred interchangeably herein as coil contact plates190A, 190B, 190C) overmolded in the rear end cap 142. During assembly ofthe stator 46, the stator windings 134 are wound around the stator teeth126 and the end cap teeth 162, and the coil contact plates 190short-circuit diagonally opposite pairs of coils 134 (e.g., 134A and134D, 134B and 134E, 134C and 134F).

With reference to FIGS. 16-17, the coil contact plates 190 are generallysemi-circular in shape and staggered to avoid contact between adjacentcoil contact plates 190. Each coil contacts plate 190 includes a firstterminal 194 (i.e., a short terminal) and a second terminal 198 (i.e., along terminal) diagonally opposite the first terminal 194. In theillustrated embodiment, the terminals 194, 198 are positioned within aslot 202 formed by the flange 170 on the rear end cap 142. The statorwindings 134 are connected to hooks 206 formed on the terminals 194,198.

In some embodiments, the rear end cap 142 and the front end cap 150 maybe manufactured separately from the stator core 106, positioned relativeto the stator core 106 using the tabs 174 and the recesses 118, and thenretained to the stator core 106 by the completed coil windings 134. Insuch an embodiment, the coil contact plates 190 may be overmolded by therear end cap 142 using, for example, an insert molding process.

In other embodiments (not shown), the stator core 106 and the coilcontact plates 190 may be insert molded together, for example, using aninjection molding process. In such an embodiment, the mold materialdefining each of the end caps 142, 150 may also overlie one or multipleof the laminations 102 in the front and the rear of the stator core 106.

In both embodiments, because the coil contact plates 190 are moldedwithin the rear end cap 142, separate means of attaching the coilcontact plates 190 to the end cap 142 is unnecessary. Also, the entirecircumferential length of the coil contact plates 190 is insulatedwithin the nonconductive mold material comprising the rear end cap 142,thereby reducing the likelihood of corrosion of the coil contact plates190 if the motor 34 is exposed to wet or damp environments.

With reference to FIG. 18, in some embodiments, the embedded stator coilcontact plates 190 include an attachable terminal 210. Specifically, theattachable terminal 210 may be secured to the coil contact plates 190after the coil contact plates 190 have been embedded within the end cap142. Advantageously, the attachable terminals 210 can be properlyselected for size (e.g., thickness), shape (e.g., hook size), material,etc., for a given application. For example, a thicker terminal 210 witha larger hook size may be required for an application requiring largercurrent values. In addition, separating the terminals 210 from the coilcontact plates 190 reduces the amount of material wasted inmanufacturing the coil contact plates 190 via stampings. The terminals210 may be coupled to the coil contact plates 190 by, for example, asoldering or welding process.

With reference to FIG. 18A, a stator end cap 142B according to anotherembodiment is illustrated. The stator end cap 142B includes threeembedded coil contact plates 190B (i.e., busbars) and six terminals194B, 198B. Specifically, three identical contact plates 190B areovermolded within the stator end cap 142B, and can be, for example,approximately 1.0 mm thick.

The terminals 194B, 198B are joined to the contact plates 190B after themolding process by, for example, a welding process. In particular, theterminals 194B, 198B connect to the contact plates 190B at a connectionportion 199. In the illustrated embodiment, the adjacent connectionportions 199 alternate between being positioned on an inner surface 200and positioned on an outer surface 201 to enable all of the terminals194B, 198B to be located in the same radial location. The terminals194B, 198B include three short terminals 194B and three long terminals198B (e.g., between approximately 1.3 mm and approximately 1.5 mm inwidth). As mentioned above, the terminals 194B, 198B can range in sizeto meet various design requirements.

With reference to FIGS. 18B and 18C, the coil contact plates (e.g., 190)and terminals (e.g., 194, 198) can be manufactured via, for example, ametal stamping process. With reference to FIG. 18B, the coil contactplate 190 can be stamped from a single piece of material 214. The singlepiece of material 214 may include an area of approximately 3190 mm², andthe coil contact plate 190 may include an area of approximately 768 mm².This results in a material scrap rate of approximately 76%.

With reference to FIG. 18C, the coil contact plate 190B is stamped froma first piece of material 214B, and the two terminals 194B, 198B areeach stamped separately. The total required amount of material necessaryfor manufacturing the coil contact plate 190B, the short terminal 194B,and the long terminal 194B is approximately 1310 mm², and the total areaof the resulting parts is approximately 840 mm². This results in amaterial scrap rate of approximately 36%.

In addition, material savings can be further increased with the designof FIG. 18C, because the thickness of the individual components can beadjusted. For example, the coil contact plate 190B can be approximately1 mm thick, while the terminals 194B, 198B can be approximately 1.3 mmto approximately 1.5 mm thick. In contrast, the single piece design ofFIG. 18B is a uniform thickness due to use of the single piece ofmaterial 214.

With particular reference to FIGS. 4-5 and 11, the rotor 50 includesindividual rotor laminations 218 stacked together to form a rotor core222. A rotor shaft 226 is positioned through a center aperture 230 inthe rotor laminations 218. The rotor shaft 226 is at least partiallysupported by a bearing 234 (FIG. 22) positioned within the hub portion66. The rotor shaft 226 defines a rotational axis 238 of the rotor 50.

The rotor laminations 218 include a non-circular outer circumference 231and a plurality of slots 232 in which permanent magnets 233 are received(FIG. 5). In the illustrated embodiment, the rotor 50 is an interiorpermanent magnet (IPM) type rotor (a.k.a., a buried magnet type rotor).In the illustrated embodiment, the plurality of slots 232 furtherinclude air barriers 235 (i.e., flux barriers) at ends of the slots 232.In addition to improving the magnetic characteristics of the rotor 50,the air barriers 235 may accommodate adhesive to aid in retaining thepermanent magnets 233 within the slots 232.

With continued reference to FIGS. 6B and 12, the stator 46 defines anouter diameter 240 of at least about 60 mm. In some embodiments, theouter diameter 240 is between approximately 70 mm and approximately 100mm. In some embodiments, the outer diameter 240 is approximately 70 mm.

With reference to FIG. 4, the stator 46 defines a length 241 within arange of approximately 68 mm to approximately 88 mm. In someembodiments, the length 241 is approximately 78 mm. The stator core 106defines a length 242 within a range of approximately 35 mm toapproximately 55 mm. In some embodiments, the length 242 of the statorcore 106 is approximately 45 mm. In some embodiments, the combinedlength of the stator 46 and the heat sink 256 is approximately 84 mm(i.e., including the motor housing 30 features that the heat sink 256mounts to, but not the rest of the housing 30). In further embodiments,the length from the heat sink 256 to back of the fan 38 is approximately95 mm, and the length from the heat sink 256 to the surface of thehousing 30 which mates to, for example, a gear case is approximately 103mm. The total weight of the stator 46 (i.e., stator core 106, end caps142, 150, and coils 134) is within a range of approximately 1.49 poundsto approximately 1.89 pounds. In some embodiments, the total weight ofthe stator 46 is approximately 1.69 pounds. The stator core 106 furtherdefines a volume within a range of approximately 72,000 mm³ andapproximately 92,000 mm³. In some embodiments, the stator core 106defines a volume of approximately 82,000 mm³.

With continued reference to FIG. 4 and the embodiment with a length 242of the stator core 106 of approximately 45 mm, the rotor 50 defines anouter diameter 243 within a range of approximately 20 mm andapproximately 40 mm. In some embodiments, the outer diameter 243 isapproximately 31.1 mm. With reference to FIG. 4, the rotor core 222defines a length 245 within a range of approximately 35 mm toapproximately 55 mm. In some embodiments, the length 245 of the rotorcore 222 is approximately 45 mm. In some embodiments, the length 245 ofthe rotor core 222 is equal to the length 242 of the stator core 106.The rotor 50 further defines a length 244 from the magnet 296 (FIG. 4)to end of the rotor core 222 of approximately 68 mm. In addition, therotor 50 defines a length 246 from the magnet 296 to the back of the fan38 of approximately 89.6 mm.

The total weight of the rotor 50 (i.e., the weight of the rotor core222, the magnets 233, the rotor shaft 226, the bearings 234 and the fan38) is within a range of approximately 0.74 pounds and approximately1.14 pounds. In some embodiments, the total weight of the rotor 50 isapproximately 0.94 pounds. The weight of the rotor core 222 is within arange of approximately 0.31 pounds to approximately 0.51 pounds. In someembodiments, the weight of the rotor core 222 is approximately 0.41pounds. In addition, the rotor core 222 defines a volume within a rangeof approximately 20,000 mm³ to approximately 30,000 mm³. In someembodiments, the rotor core 222 volume is approximately 25,170 mm³.

With reference to FIGS. 23-26, the PCB assembly 42 includes a firstprinted circuit board 248 (i.e., a power circuit board), a secondprinted circuit board 252 (i.e., a rotor position sensor board), and aheat sink 256. The heat sink 256 defines a first side 260 to which thefirst printed circuit board 248 is coupled to and defines a second side264 to which the second printed circuit board 252 is coupled to. Inother words, the heat sink 256 is positioned between the first andsecond PCBs 248, 252. As such, the heat sink 256 is positioned andoperable to draw heat from both the first PCB 248 and the second PCB252.

The PCB assembly 42 is coupled to the rear end 70 of the motor housing30 opposite the front end 82 from which the rotor shaft 226 protrudes.The PCB assembly 42 is fastened to the motor housing 30 by the fasteners60 (FIGS. 4 and 6A) equally spaced about the periphery of the motorhousing 30. With reference to FIG. 3, the second terminals 198 extendthrough the heat sink 256 and are electrically connected to the powercircuit board 248, while the first terminals 194 do not protrude throughthe heat sink 256. Particularly, the terminals 198 of the coil contactplates 190 are connected, respectively to the U, V, W phases of theinverter bridge 378.

In some embodiments, where the power circuit board 248 is locatedelsewhere within the power tool 10 as described above, the coil contactplates 190 may be connected to the power circuit board 248 by leadwires. Lead wires may be connected to the second terminals 198 (e.g., toholes in the second terminals 198) and routed to the power circuit board248 within the power tool housing.

In some embodiments, rather than being attached to the motor housing,the power circuit board 248 may be located on a casting elsewhere withinthe combination 10. For example, the power circuit board 248 may belocated in a handle portion of the power tool housing or adjacent themotor assembly 26 in a motor housing portion of the combination 10.However, the rotor sensor board 252 may remain with the motor assembly26.

With continued reference to FIG. 24, the power circuit board 248includes a plurality of switches 272 (e.g., FETs, IGBTs, MOSFETs, etc.).The power source (the battery pack 18) provides operating power to themotor 34 through the switches 272 (e.g., an inverter bridge). In theillustrated embodiment, the power circuit board 248 includes terminals276 to receive the DC power from the power source. By selectivelyactivating the switches 272, power from the power source is selectivelyapplied to coils of the motor 34 to cause rotation of the rotor 50.

The power circuit board 248 includes a first, generally flat surface 280facing the heat sink 256 and a second surface 284 opposite the firstsurface 280. The switches 272 and capacitors 288 associated with thepower circuit board 248 are positioned on the second surface 284. Thefirst surface 280 is held in contact with the heat sink 256 such thatheat generated by the power circuit board 248 (e.g., heat generated bythe switches 272) is transferred by conduction to the heat sink 256where it is subsequently dissipated.

The power circuit board 248 also includes holes 288 through which theterminals 198 of the coil contact plates 190 protrude. The holes 288 areconnected to the U, V, and W terminals of the inverter bridge,respectively, via printed electrical traces on the power circuit board248. Accordingly, individual electric wires are not required toelectrically connect the switches 272 to the coil contact plates 190.Additionally, recesses (similar to recesses 314) are provided on theouter circumference of the power circuit board 248 through which thefasteners 60 extend.

With reference to FIG. 23, the rotor position sensor board 252 includesa plurality of Hall-effect sensors 292, and the motor 34 includes aring-shaped permanent magnet 296 mounted on the rotor shaft 226. Thering magnet 296 is affixed to the rotor shaft 226 and co-rotates withthe rotor shaft 226, emanating a rotating a magnetic field that isdetectable by the Hall-effect sensors 292. The ring magnet 296 isrotationally aligned with the magnets 233 of the rotor 50. Specifically,the hub portion 62 defines a central aperture 302 into which the bearing234 for supporting the rotor shaft 226 is interference-fit and where thering magnet 296 is received (FIGS. 4 and 7). In the illustratedembodiment, the rotor position sensor board 252 is received within arecess 315 formed on the second side 264 of the heat sink 256.

A connection portion 306 is provided at one end of the rotor positionsensor board 252 to connect with a mating connection portion 307 on thepower circuit board 248. In this manner, power is provided to the rotorposition sensor board 252 via the mating connection terminals 306, 307,and the motor information feedback from the Hall-effect sensors 292 istransmitted to the motor controller 374 via the power circuit board 248.In some embodiments, the power circuit board 248 and the rotor positionsensor board 252 may be combined on a single motor controller PCB (notshown).

With reference to FIG. 26, the heat sink 256 includes holes 310 alignedwith the corresponding holes 288 in the power circuit board 248 throughwhich the terminals 198 pass and connect to the power circuit board 248,as mentioned above. Recesses 314 are also provided on the outercircumference of the heat sink 256 through which the fasteners 60extend. In some embodiments, a low-pressure molding (not shown) isprovided with the heat sink 256 to support the rotor position sensorboard 252 proximate the connection portion 306, against the heat sink256.

The opposite end of the rotor position sensor board 252 is fastened tothe heat sink 256 to ensure that the rotor position sensor board 252remains in contact with the heat sink 256 and to reduce the tolerancestack up with reference to the ring magnet 296. In some embodiments, thelow-pressure molding also insulates solder joins for power leads and aribbon cable connector from contaminations. In addition, thelow-pressure molding may extend to the edges of the holes 310 in theheat sink 256 to provide electrical insulation between the terminals 198and the heat sink 256. The heat sink 256 may also be hard-coat anodizedor carbon coated to provide electrical isolation from the terminals 198.

The Hall-effect sensors 292 output motor feedback information, such asan indication (e.g., a pulse) when the Hall-effect sensors 292 detect apole of the magnet 296 attached to the rotating shaft 226 of the motor34. Based on the motor feedback information from the Hall-effect sensors292, the motor controller 374 may determine the rotational position,velocity, and/or acceleration of the shaft 226.

The motor controller 374 also receives control signals from the userinput. The user input may include, for example, a trigger switch, aforward/reverse selector switch, a mode selector switch, etc. Inresponse to the motor feedback information and the user control signals,the motor controller 374 transmits control signals to the switches 272to drive the motor 34. By selectively activating the switches 272, powerfrom the power source is selectively applied to coils 134 to causerotation of the shaft 226. In some embodiments, the motor controller 374may also receive control signals from an external device such as, forexample, a smartphone wirelessly through a transceiver (not shown).

The heat sink 256 includes a base 318 with fins 322 and posts 326extending from the second side 264 of the heat sink 256. The fins 322and the posts 326 can be utilized to improve the cooling capacity of theheat sink 256 and/or structurally support the heat sink 256 with respectto the rest of the motor assembly 26.

In some embodiments, the heat sink 256 defines a thickness 330 within arange of approximately 2 mm to approximately 6 mm. In some embodiments,the fins 322 and the posts 326 extend from the base 318 to define adimension 334 within a range of approximately 11 mm to approximately 15mm. In some embodiments, the heat sink 256 defines an outer diameter 338within a range of approximately 65 mm to approximately 85 mm. In someembodiments, the outer diameter 338 of the heat sink 256 isapproximately 75 mm.

With reference to FIG. 23, the printed circuit board 248 defines anouter diameter 338 within a range of approximately 65 mm toapproximately 85 mm. In some embodiments, the outer diameter 338 of theprinted circuit board 248 is approximately 75 mm. The printed circuitboard 248 defines an area within a range of approximately 3300 mm² toapproximately 5700 mm². The printed circuit board 248 defines a height,including the FETs 386, 390, within a range of about 5 mm to about 10mm. The printed circuit board 248 defines a volume within a range ofapproximately 16,500 mm³ to approximately 57,000 mm³.

With reference to FIG. 4, the heat sink 256 is positioned within theairflow generated by the fan 38. By positioning the PCB assembly 42 onthe rear 70 of the motor housing 30, cooling of the PCB assembly 42 ismaximized. With reference to FIGS. 6B and 27, the fan 38 is coupled tothe rotor shaft 226 for co-rotation therewith. In particular, a fitting342 is mounted around the rotor shaft 226, and the fitting 342 couplesthe fan 38 to the rotor shaft 226. The fan 38 includes a centralaperture 346 and a set of fan blades 350.

With reference to FIG. 28, experimental results for current 354,efficiency 358, speed 362, and motor power output 366 are illustratedfor the high power DC tool systems 14. The results are for forward andreverse operation of the high power DC tool system 14 with the diameter240 of the stator 46 approximately 70 mm and the length 242 of thestator core 106 approximate 45 mm. In some embodiments, the peak poweroutput of the motor assembly 26 (with the stator stack length 106 ofapproximately 45 mm) is within a range of approximately 2200 W toapproximately 2600 W. In some embodiments, the peak power of the motorassembly 26 is approximately 2400 W during both forward operation (i.e.,the green traces) and reverse operation (i.e., the red traces).

With reference to FIG. 1B, the combination 10 additionally includes arelay 398 in addition to the electronics assembly 22 and the motorassembly 26. The electronics assembly includes a motor controller 374,an inverter bridge 378, and a trigger assembly 382. As described above,with respect to FIGS. 3-7, the motor assembly 26 includes the motor 34and the second PCB 252 including the Hall-effect sensor 292. Theelectronics assembly 22 may also include additional user inputs (notshown), for example, a mode selector switch, a speed dial, a clutchsetting unit, etc. In some embodiments, the electronics assembly 22 mayinclude a power switch (not shown) in addition to or in place of thetrigger assembly 382.

In some embodiments, the motor controller 374 is implemented as amicroprocessor with a separate memory. In other embodiments, the motorcontroller 374 may be implemented as a microcontroller (with memory onthe same chip). In other embodiments, the motor controller may beimplemented partially or entirely as, for example, a field programmablegate array (FPGA), an application specific integrated circuit (ASIC),hardware implemented state machine, etc., and the memory may not beneeded or modified accordingly.

The motor controller 374 controls the operation of the motor 34 throughthe inverter bridge 378. With reference to FIG. 1B, the motor controller374 is communicatively coupled to the trigger assembly 382 and theHall-effect sensor 292. The trigger assembly 382 may include, forexample, a potentiometer, a distance sensor, etc., to determine andprovide an indication of the distance the trigger is pulled to the motorcontroller 374. The motor controller 374 determines a motor speed basedon an input from the Hall-effect sensor 292. The motor controller 374performs an open loop or closed loop control of the motor 34 through theinverter bridge 378 based on the signals received from the triggerassembly 382 and the Hall-effect sensor 292.

With reference to FIG. 29, the inverter bridge 378 controls the powersupply to the three-phase (e.g., U, V, and W) motor 34 of the power tool14. The inverter bridge 378 includes high-side FETs 386 and low-sideFETs 390 for each phase of the motor 34. The high-side FETs 386 and thelow-side FETs 390 are controlled by corresponding gate drivers 394implemented in the motor controller 374.

In some embodiments, the inverter bridge 378 may include more than onehigh-side FET 386 and more than one low-side FET 390 per phase toprovide redundant current paths for each phase. In addition, in someembodiments, the gate drivers 394 may be implemented on a separateintegrated circuit provided on the inverter bridge 378. Although FIG. 29illustrates only one set of a high-side FET 386 and a low-side FET 390,the inverter bridge 378 includes three sets of high-side FETs 386 andlow-side FETs 390, one for each phase of the motor 34. In addition, themotor controller 374 includes three gate drivers 394, one for each phaseof the motor 34.

The drain of the high-side FETs 386 is connected to the battery powersupply, and the source of the high-side FETs 386 is connected to themotor 34 (e.g., phase coils 134 of the motor 34) to provide the batterypower supply to the motor 34 when the high-side FETs 386 are closed. Inother words, the high-side FETs 386 are connected between the batterypower supply and the motor phase coils 134.

The drain of the low-side FETs 390 is connected to the motor 34 (e.g.,phase coils 134 of the motor 34), and the source of the low-side FETs390 is connected to ground. In other words, the low-side FETs 390 areconnected between the motor phase coils 134 and ground. The low-sideFETs 390 provide a current path between the motor phase coil and groundwhen closed.

When the FETs 386, 390 are closed (or ON), the FETs 386, 390 allow acurrent flow through the phase coils 134. In contrast, when the FETs386, 390 are open (or OFF), the FETs 386, 390 prevent a current flowthrough the phase coils 134. The FETs 386, 390 of the illustratedconstructions are characterized by relatively high drain-sourcebreakdown voltage (e.g., between 30 V to 50 V), relatively highcontinuous drain current (e.g., between 300 A to 600 A), relatively highpulsed drain current (e.g., over 1200 A), and a drain-source on-stateresistance between 0.3 mΩ and 0.9 mΩ.

In contrast, FETs used in existing power tools were not rated for suchhigh voltage and current characteristics. Accordingly, such existingpower tools would not be capable of handling such high current andvoltage characteristics. In addition, FETs used in the existing powertools were driven with lower current. As such, FETs having an internalresistance below 1.5 mΩ could not be used in existing power tools todrive the motor. Because the FETS 386, 390 have relatively smallresistance compared to FETs of existing power tools, the heatdissipation by the inverter bridge 378 is significantly reduced.

The gate drivers 394 provide a gate voltage to the FETs 386, 390 tocontrol the FETs 386, 390 to open or close. The gate drivers 394 receivea power supply (e.g., a low-voltage power supply) from the battery pack18. In some embodiments, the motor controller 374 and the gate drivers394 may control only the low-side FETs 390 to operate the motor 34. Inother embodiments, the motor controller 374 and the gate drivers 394 maycontrol only the high-side FETs 386 to operate the motor 34. In yetother embodiments, the motor controller 374 and the gate drivers 394alternate between controlling the high-side FETs 386 and the low-sideFETs 390 to operate the motor 34 and to distribute the thermal loadbetween the FETs 386, 390.

In some embodiments, the inverter bridge 378 may also include a currentsensor (not shown) provided in the current path to detect a currentflowing to the motor 34. The output of the current sensor is provided tothe motor controller 374. The motor controller 374 may control the motor34 further based on the output of the current sensor.

As described above, the relay 398 is provided between the battery pack18 and the electronics assembly 22. When the relay 398 is closed, therelay 398 allows a current to flow through to the electronics assembly22, and, when the relay 398 is open, the relay 398 prevents a currentfrom flowing to the electronics assembly 22. The relay 398 provides anunder-voltage protection to the FETs 386, 390 and may also prevent acurrent flow through to the FETs 386, 390 in a failure condition of themotor controller 374. The relay 398 may include an electromechanicalrelay or a semiconductor based solid state relay.

The relay 398 is controlled by the motor controller 374 and the triggerassembly 382. For example, the relay 398 may include a logic circuit(not shown) that receives an input from the motor controller 374 and thetrigger assembly 382. The relay 398 may close to allow a dischargingcurrent to flow through only when both inputs are high. That is, therelay 398 may close only when the trigger is actuated, the motorcontroller 374 is functioning, and the motor controller 374 indicatesthere are no faults in the power tool 14. The relay 398 may open wheneither of the inputs is low. For example, the relay 398 may prevent adischarging current to flow through when either the trigger is notactuated, when the motor controller 374 has failed, or when the motorcontroller 374 indicates a fault condition in the power tool 14.

In some embodiments, the motor controller 374 performs a FET check atthe start of every trigger pull. The motor controller 374 successivelyturns on each FET 386, 390 to ensure all FETs 386, 390 are functioning.When the motor controller 374 detects that all FETs 386, 390 arefunctioning, the motor controller 374 continues normal operation of thepower tool 14. When the motor controller 374 detects that one of theFETs 386, 390 has failed, the motor controller 374 may temporarily orpermanently disable the power tool 14 to prevent the operation of thepower tool 14.

FIG. 30 is a flowchart illustrating one example method 402 of checkingFETs 386, 390. The method 402 includes providing a test signal to theall the FETs 386, 390 (at block 406). As described above, the motorcontroller 374 successively turns on each FET 386, 390. The method 402also includes determining whether all the FETs 386, 390 are functioning(at block 410). The motor controller 374 determines whether the FETs386, 390 are functioning or have failed based on the test signals. Forexample, the motor controller 374 may monitor an input and output of theFETs 386, 390 to determine whether the FETs 386, 390 are functioningwhen the test signal is provided.

When the motor controller 374 determines that all FETs 386, 390 arefunctioning, the motor controller 374 allows an operation of the powertool 14 (at block 414). For example, the motor controller 374 continuesto provide a high signal to the relay 398 to allow normal operation ofthe power tool 14. When the motor controller 374 determines that atleast one of the FETs 386, 390 has failed, the motor controller 374disables the power tool 14 (at block 418). The motor controller 374 maytemporarily or permanently disable the power tool 14. For example, themotor controller 374 provides a low signal to the relay 398 to prevent adischarge current from flowing to the FETs 386, 390.

Existing power tools rely on stall current to limit the current drawn bythe power tool 14. However, in the illustrated constructions, becausethe current flowing through the FETs 386, 390 is higher in theillustrated power tools 14 and the impedance offered by the FETs 386,390 (and by other components in the system 10, especially the batterypack 18 and the motor 34) is lower, stall current can no longer berelied upon because the higher current may cause the FETs 386, 390 tofail. Accordingly, a hysteretic current control is used to limit currentconsumption of the power tool 14. In short, the motor controller 374reduces the PWM cycle to the FETs 386, 390 when the current exceeds apredetermined threshold.

FIGS. 31A-31C illustrates a timing diagram of a voltage signal providedto the inverter bridge 378. FIG. 31A shows a PWM signal 422 during anormal operation of the power tool 14. As can be seen, the PWM signal422 provided to the inverter bridge has a constant duty cycle (e.g.,50%). In some embodiments, the duty cycle of the PWM signal 422 may varywith the distance the trigger is pulled.

FIG. 31B shows a PWM signal 426 during a hysteretic current controloperation of the power tool 14. When the motor controller 374 determinesthat a current flowing (or to flow) to the motor 34 exceeds apredetermined current threshold, the motor controller 374 varies (e.g.,reduces) the duty cycle of the PWM signal 426 to limit the current. Forexample, the motor controller 374 may decrease the duty cycle to 40%.The motor controller 374 may return to normal operation when the currentis within a normal range.

FIG. 31C shows a PWM signal 430 during the hysteretic current controloperation when the motor controller 374 controls the duty cycle as afunction of the current. For example, for each positive voltage signalof the PWM signal 434, the motor controller 374 turns the voltage signaloff when the current exceeds the predetermined threshold. Accordingly,each subsequent positive voltage signal may have a different duty cycle.For example, the first positive voltage signal 434 may have a 50% dutycycle when the current does not exceed the predetermined threshold. Forthe second positive voltage signal 438, the motor controller 374 mayturn off the signal once the current exceeds the predeterminedthreshold, which may result in, for example, an 40% duty cycle.Similarly, for a third positive voltage signal 442, the duty cycle maybe further reduced to 30% based on the current exceeding thepredetermined threshold earlier.

FIG. 32 is a flowchart illustrating one example method 446 of hystereticcurrent control. The method 446 includes providing a voltage signalhaving a first duty cycle to the FETs 386, 390 (at block 450). Asdescribed above, the first duty cycle may be 100% or may be inproportion to the distance to which the trigger is pulled. The method446 also includes monitoring the current provided to the FETs 386, 390(at block 454). The monitored current may be an instantaneous current, aslow moving current average, a fast moving current average, etc. Themethod 446 further includes determining whether the current is above apredetermined current threshold (at block 458). In some embodiments, thepredetermined current threshold is within the range of approximately 140A to 280 A.

When the current exceeds the predetermined current threshold, the method446 includes providing a voltage signal having a second duty cycle,lower than the first duty cycle, to the FETs (at block 460). Asdescribed above, the duty cycle may be reduced as a function of thecurrent. For example, the duty cycle may be reduced to 80% or 60% of theduty cycle in proportion to the distance to which the trigger is pulled.When the current does not exceed the predetermined threshold, the method426 continues providing the voltage signal having the first duty cycleto the FETs 386, 390. In addition, the method 426 continues to monitorthe amount of current provided to the FETs 386, 390.

The relay 398 and the inverter bridge 378 define power electronics ofthe power tool 14. A printed circuit board including the motorcontroller 374 defines control electronics of the power tool 14. Thepower electronics and the control electronics may be distributed withinthe power tool housing. The printed circuit board including the motorcontroller 374 defines a length within a range of approximately 40 mm toapproximately 60 mm, a width within a range of approximately 25 mm toapproximately 40 mm, and a height (including of all fixed non-wirecomponents) within a range of approximately 5 mm to approximately 15 mm.The printed circuit board including the motor controller 374 defines anarea within a range of 1000 mm² to 2400 mm² and a volume within a rangeof approximately 5000 mm³ to approximately 36000 mm.

The relay 398 (not including the plugs) defines a length within a rangeof approximately 45 mm to 65 mm, a width within a range of approximately30 mm to 50 mm, and a volume within the range of 54,000 mm³ and 180,000mm. Put together, the power electronics have an area within the range ofapproximately 5200 mm² to approximately 10,500 mm². Put together, thepower electronics have a volume within the range of approximately 48,500mm³ to approximately 150,000 mm³.

In some embodiments, 10-gauge wire is used to connect the power sourceto the inverter bridge 378. 10-gauge wire offers improved thermal loadcapabilities.

FIGS. 33-62 illustrate several embodiments of the battery pack 18. Withreference to FIGS. 33-42, a battery pack 18 having a 5S3P configuration(a set of 5 cells in series, 3 sets in parallel) is illustrated inaccordance with some embodiments. The battery pack 18 includes a batterypack housing 462 and a terminal block 466 provided on the battery packhousing 462. The battery pack housing 462 encloses the components of thebattery pack 18 including battery cells, a battery controller, etc. Whenthe battery pack 18 is attached to the power tool 14, the terminal block466 is coupled to a terminal block (not shown) of the power tool 14. Thebattery pack 18 provides discharge current to the power tool 14 throughthe terminal block 466.

With reference to FIGS. 43-52, a battery pack 18A having a 5S2Pconfiguration is illustrated in accordance with some embodiments. Withreference to FIGS. 53-62, a battery pack 18B having a 5S1P configurationis illustrated in accordance with some embodiments.

FIG. 63 is a simplified block diagram of the battery pack 18. Thebattery pack 18 includes the battery cells 470, a battery controller474, a resistor 478, and battery pack terminals 482. The batterycontroller 474 may be implemented in ways similar to the motorcontroller 374. The battery controller 474 communicates with the motorcontroller 374 through the terminal block 466.

The battery pack 18 may include one or more battery cell stringsconnected in parallel, each having a number (e.g., five or more) ofbattery cells connected in series to provide a desired discharge output(e.g., nominal voltage (e.g., between about 16V and about 20V) andcurrent capacity). Accordingly, the battery pack 18 may include “5S1P”(see FIGS. 53-62), “5S2P” (see FIGS. 43-52), “5S3P” (see FIGS. 33-42),etc., configurations. In other embodiments, other combinations ofbattery cells 470 are also possible.

Each battery cell 470 may have a nominal voltage between 3 V and 5 V andmay have a nominal capacity between 3 Ah and 5 Ah. The battery cells 470may be any rechargeable battery cell chemistry type, such as, forexample, Lithium (Li), Lithium-ion (Li-ion), other lithium-basedchemistry, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), etc.

The battery pack 18 provides relatively higher current than existingbattery packs. However, this higher current output may damage a motorcontroller during a start-up time of the power tool 14. To prevent thisdamage to the motor controller, the battery pack 18 includes theresistor 478 to initially provide a reduced current at start up. Thebattery pack 18 provides two current paths to the battery pack terminals482.

FIG. 73 is a block diagram showing the two paths between the batterycells 470 and the battery pack terminals 482. In the first current path,the battery cells 470 are connected to the battery pack terminals 482through the resistor 478 and positive thermal coefficient (PTC) elements480 (FIG. 64A). The resistor 478 is a high-resistance resistor used toreduce the amount of current flow in the first current path. Each PTCelement 480 is a temperature-dependent resistor, the resistance of whichincreases as its temperature increases. Accordingly, if the connectionbetween the battery cells 470 and the battery pack terminals 482 isshorted for a period of time (e.g., due to a malfunction) causing thecurrent to flow though the PTC elements 480 and produce heat, theresistance of the PTC elements 480 will increase until the PTC elements480 essentially act as an open circuit to prevent the battery pack 18and/or the power tool 10 from overheating.

In the second path, the battery cells 470 are connected to the batterypack terminals through a switch 486 (FIG. 64B). The switch 486 may beimplemented as a bi-polar junction transistor (BJT), a field effecttransistor (FET), etc., having a lower resistance than the resistor 478.The battery controller 474 provides the control signals to open or closethe switch 486. When the battery pack 18 is coupled to the power tool 10and the trigger is not pulled and/or for a brief period of time afterthe trigger is pulled, the switch 486 acts as an open circuit, andcurrent is delivered through the resistor 478 and the PTC elements 480to power the power tool electronics without causing overheating.Alternatively, when the trigger is pulled and/or after the brief periodof time after the trigger is pulled, the transistor acts as a shortcircuit, with the current from the battery cells 470 bypassing theresistor 478 and the PTC elements 480 to provide power to the power tool10.

FIG. 65 is a flowchart of one example method 490 of operating thebattery pack 18. The method 490 includes connecting the resistor 478 ina current path of the battery pack 18 (at block 494). In operation, uponinsertion of the battery pack 18 (or after the battery pack 18 has beenidle on the power tool 10), the resistor 478 is connected between thebattery cells 470 and the battery pack terminals 482 by opening theswitch 486. Accordingly, due to the higher resistance of this path, thebattery pack 18 provides reduced current to start-up the power tool andthe motor controller.

The method 490 also includes determining that a predetermined amount oftime has elapsed after a trigger activation (at block 498) and removingthe resistor 478 from the current path when the predetermined amount oftime has elapsed after the trigger activation (at block 502). When thetrigger is pulled and after a predetermined time period (e.g., 1-2 ms),the switch 486 is closed to short out the resistor 478 of the currentpath. Due to the lower resistance of this path, the battery pack 18provides high current to operate the power tool 14.

In some embodiments, additionally or alternatively, protection may beprovided to the battery pack 18 by using a fuse in the current path ofthe battery pack 18. Referring to FIG. 77, a fuse 670 is coupled betweenthe negative terminals of the battery cells 470 and the terminal block482. The fuse 670 may be a Copper alloy such as a FAS 680 Copper-Tinalloy or an EFTEC copper alloy that is conducive to welding and has highthermal and electrical conductivity. As shown in FIG. 78, the fuse 670may be welded or soldered to the bus bar connecting the negativeterminals of the battery cells 470. The fuse 670 is connected to thecircuit board including the resistor 478, the PTC elements 480, and theswitch 482.

The bus bar connecting the positive terminals of the battery cells 470is provided underneath the battery pack terminals 482, while thenegative terminals of the battery cells 470 are provided on the oppositeside of the battery pack 18 from the battery pack terminals 482. Thenegative side of the battery pack 18 also has a large sense resistor anda heat sink (e.g., copper) for the FET. Placement of the fuse 670 on thenegative side of the battery cells 470 thus allows heat generated duringa hard short (e.g., 80 milliohms and below) of the fuse 670 to sink intothe heat sink and to be isolated from the battery pack terminals 482.

In some embodiments, the battery pack terminals 482 may be placed closerto the bus bar connecting the negative terminals of the battery cells470 and on the opposite side of the battery pack 18 from the positiveterminals of the battery pack 18. In these embodiments, the fuse 670 maybe connected to the positive terminals of the battery cells 470.

In some embodiments, the power tool 14 may implement a cell stringswitching mechanism to limit damage to the motor controller due tohigher current. FIG. 66 is a simplified block diagram of one example ofa 5S3P configuration of the battery pack 18.

In the illustrated construction, the battery pack 18 includes three cellstrings 506A-506C of five series connected battery cells. Each cellstring 506A-506C is individually monitored by one of analog front ends510A-510C. The second cell string 506B and the third cell string 506Care connected to the battery pack terminals 482 through a first switch514 and a second switch 518 respectively.

When closed, the first switch 514 connects the second cell string 506Bto the battery pack terminals 482 and, when open, disconnects the secondcell string 506B from the battery pack terminals 482. Similarly, whenclosed, the second switch 518 connects the third cell string 506C to thebattery pack terminals 482 and, when open, disconnects the third cellstring 506C from the battery pack terminals 482 when open. The firstswitch 514 and the second switch 518 are controlled to open and close bythe battery controller 474.

In some embodiments, a discharging switch (not shown) may be connectedin a discharging path of the battery pack 18 between the cell strings506A-506C and the battery pack terminals 482. In addition, the batterypack 18 may also include a charging switch 522 connected between thecell strings 506A-506C and a charging terminal 526 of the battery pack18.

FIG. 67 is a flowchart of a method 530 of switching cell strings506A-506C according to one embodiment. The method 530 includesconnecting, using the battery controller 474, a first cell string 506Ato the battery pack terminals 482 during start-up (at block 534). Forexample, the battery controller 474 opens the first switch 514 and thesecond switch 518 and closes the discharging switch to connect only thefirst cell string 506A to the power tool 14 and, thus, provide a reducedcurrent to power up the motor controller.

The method 530 also includes determining that a predetermined amount oftime has elapsed (at block 438) and connecting the second cell string506B when the predetermined amount of time has elapsed (at block 542).The battery controller 474 may start a timer after start-up and when thetimer expires (e.g., after 200 ms), the battery controller 474 may closethe first switch 514 and the second switch 518 to connect the secondcell string 506B and the third cell string 506C to the battery packterminals 482. The battery controller 474 may close the first switch 514and the second switch 518 around the same time or may close the secondswitch 518 a second predetermined amount of time after closing the firstswitch 514.

FIG. 68 is a simplified block diagram of another example of a 5S3Pconfiguration of the battery pack 18. In the example illustrated, thefirst cell string 506A is monitored by the first analog front end 510A,and the second cell string 506B and the third cell string 506C aremonitored by the second analog front end 510B, thereby reducing thenumber of analog front ends 458. The second cell string 506B and thethird cells string 510C are connected to the battery pack terminals 482through a first switch 546. When closed, the first switch 546 connectsthe second cell string 506B and the third cell string 506C to thebattery pack terminals 482 and, when open, disconnects the second cellstring 506B and the third cell string 506C from the battery packterminals 482. The first switch 546 is controlled to open and close bythe battery controller 474.

FIG. 69 is a flowchart of a method 550 of switching cell strings506A-506C according to another embodiment. The method 550 includesconnecting, using the battery controller 474, a first cell string 506Ato the battery pack terminals 482 during start-up (at block 554). Forexample, the battery controller 474 opens the first switch 546 andcloses the discharging switch to connect only the first cell string 506Ato the power tool 10 and provide a reduced amount of current to power upthe motor controller 374.

The method 550 also includes determining that a predetermined amount oftime has elapsed (at block 558) and connecting the second cell string506B when the predetermined amount of time has elapsed (at block 562).The battery controller 474 may start a timer after start-up and when thetimer expires (e.g., after 200 ms), the battery controller 474 may closethe first switch 546 to connect the second cell string 506B and thethird cell string 506C to the battery pack terminals 482.

FIG. 70 is a simplified block diagram of another example of a 5S3Pconfiguration of the battery pack 18. In the example illustrated, the5S3P configuration is similar to the 5S3P configuration shown in FIG.68. However, the 5S2P configuration formed by the second cell string506B and the third cell string 506C includes a second switch (not shown)dividing the 5S2P configuration into a 3S2P configuration and a 2S2Pconfiguration. That is, when the second switch is open, only the 3S2Pconfiguration is connected between the first switch 498 and ground. Whenthe second switch is closed, the 5S2P configuration formed by the secondcell string 506B and the third cell string 506C is connected between thefirst switch 498 and ground. As described above, the first switch 546and the second switch are controlled by the battery controller 474 toselectively connect the first cell string 506A, the 3S2P configuration,and the 5S2P configuration to the battery pack terminals 482.

FIG. 71 is a flowchart of a method 562 of switching cell strings506A-506C according to another embodiment. The method 562 includesconnecting, using the battery controller 474, a first cell string 506Aand a first configuration of battery cells to the battery pack terminals482 during start-up (at block 566). For example, the battery controller474 opens the second switch and closes the first switch 546 and thedischarging switch to connect only the first cell string 506A and the3S2P configuration to the power tool 14 to provide a reduced amount ofcurrent to power up the motor controller 374.

The method 562 also includes determining that a predetermined amount oftime has elapsed (at block 570) and connecting the second cell string506B when the predetermined amount of time has elapsed (at block 574).The battery controller 474 may start a timer after start-up and when thetimer expires (e.g., after 200 ms), the battery controller 474 may closethe second switch to connect the 5S2P configuration formed by the secondcell string 506B and the third cell string 506C to the battery packterminals 482.

In some embodiments, the battery pack terminals 482 may be made of F-Tecterminal to offer better thermal distribution capabilities anddurability.

Battery packs having cells with Lithium-ion chemistry may be subject toshipping regulations. Such shipping regulations may limit the voltageand/or power capacity of the battery pack being shipped. In order tocomply with such regulations, battery packs 18 may be shipped withsubcores and/cell strings 506A-506C of the battery cells 470disconnected from each other. Battery packs 18 may include a switch, asdescribed below, which connects the subcores or cell strings 506A-506Ctogether when the battery pack 18 is in use. A similar switch andswitching arrangement is described and illustrated in U.S. ProvisionalPatent Application No. 62/435,453, filed Dec. 16, 2016, the entirecontents of which is hereby incorporated by reference.

The battery pack 18 includes a switch 578 extending from the housing462. The switch 578 is configured to be in a first position and a secondposition. When in the first (e.g., “OFF”) position, electricalcomponents (for example, the subcores or the cell strings 506A-506C) ofthe battery pack 18 contained within the housing 462 electricallydisconnected from each other. When in the second (e.g., “ON”) position,electrical components (for example, the subcores or the cell strings506A-C) are electrically connected to each other. The switch 578 may bemanipulated by a user from the first position to a second position bypressing the switch 578.

FIGS. 72A-72B illustrate the switch 578 in accordance with someembodiments. As discussed above, the switch 578 is configured to be inthe first position (FIG. 72A) and the second position (FIG. 72B). Theswitch 578 includes a shell 582, terminals 586 a, 586 b, 586 n, aconductive bus 590, and a non-conductive layer 594. The shell 582 may beformed of plastic or a similar material. The shell 582 is slidinglycoupled to the housing 462, while the conductive bus 590 andnon-conductive layer 594 are coupled, or integral to, the housing 462,such that the shell 582 is slidingly coupled to the conductive bus 590and non-conductive layer 594. The shell may include one or more recesses598, a front stop member 602, and a rear stop member 606.

Although illustrated as having six terminals 586 a-586 f, in otherembodiments (not shown), the battery pack 18 may have fewer or moreterminals 586. Each terminal 586 has a first end coupled to the shell582 and electrically coupled to the subcores (for example, via subcoreterminals). Each terminal 586 has a second end configured to slidinglycontact, when the switch 578 is in the off position, the non-conductivelayer 594 and, when the switch 578 is in the on position, the conductivebus 590.

As illustrated in FIGS. 72A-72B, in some embodiments, the conductive bus590 and non-conductive layer 594 are coupled to a user-interface (e.g.,a portion projecting out of the housing and configured to be operable bythe user) via a protective member 610 having one or more projections 614and forming an aperture 618. The projections 614 engage with the one ormore recesses 598 of the shell 582 to prevent unwanted movement betweenthe first position and the second position. The front stop member 602 ispositioned within the aperture 618 and engages the protective member 610to prevent the conductive bus 590 and non-conductive layer 594 fromsurpassing the first position, when moving from the second position tothe first position. The rear stop member 606 prevents the conductive bus590 and non-conductive layer 594 from surpassing the second position,when moving from the first position to the second position.

With reference to FIG. 39, the battery pack 18 defines a length 622within a range of approximately 140 mm to approximately 155 mm. In someembodiments, the length 622 is approximately 152.25 mm. With referenceto FIG. 38, the battery pack 18 defines a width 626 within a range ofapproximately 75 mm to approximately 90 mm. In some embodiments, thewidth 626 is approximately 84 mm. With reference to FIG. 37, the batterypack 18 defines a height 630 within a range of approximately 90 mm toapproximately 110 mm. In some embodiments, the height 630 isapproximately 99 mm. The volume of the battery pack 18 is between about945,000 mm³ to about 1,534,500 mm³ (e.g., about 1,022,954 mm³). Thetotal weight of the battery pack 18 is within a range of approximately 3lbs. to approximately 4 lbs. In some embodiments, the total weight ofthe battery pack 18 is approximately 3.426 lbs. (about 1,554 grams (g)).

In some other embodiments, the width may increase about 1 mm to about 3mm to about 85 mm to about 87 mm. In such embodiments, the total weightof the battery pack 18 may increase to about 3.48 lbs. to about 3.5 lbs.(about 1,579 g to about 1,588 g).

The battery pack 18 has an AC internal resistance (ACIR) within a rangeof approximately 18 milliohms to approximately 23 milliohms. The batterypack 18 has a DC internal resistance (DCIR) within a range ofapproximately 15 mΩ to approximately 25 mΩ. In some embodiments, theDCIR of the battery pack 18 is about 21 mΩ.

With reference to FIG. 49, the battery pack 18A defines a length 634within a range of approximately 130 mm to approximately 145 mm. In someembodiments, the length 634 is approximately 138.9 mm. With reference toFIG. 48, the battery pack 18A defines a width 638 within a range ofapproximately 75 mm to approximately 90 mm. In some embodiments, thewidth 638 is approximately 84 mm. With reference to FIG. 47, the batterypack 18A defines a height 642 within a range of approximately 75 mm toapproximately 85 mm. In some embodiments, the height 642 isapproximately 81.9 mm. The volume of the battery pack 18 is betweenabout 730,000 mm³ to about 1,110,000 mm³ (e.g., about 766,202 mm³). Thetotal weight of the battery pack 18A is within a range of approximately2 lbs. to approximately 3 lbs. In some embodiments, the total weight ofthe battery pack 18A is approximately 2.3 lbs. (about 1049.5 grams).

The battery pack 18A has an ACIR within a range of approximately 25milliohms to approximately 30 milliohms. The battery pack 18A has a DCIRwithin a range of approximately 27 mΩ to approximately 37 mΩ. In someembodiments, the DCIR of the battery pack 18A is about 32 mΩ.

With reference to FIG. 53, the battery pack 18B defines a length 646within a range of approximately 130 mm to approximately 145 mm. In someembodiments, the length 646 is approximately 139.9 mm. The battery pack18B defines a width 650 within a range of approximately 75 mm toapproximately 90 mm. In some embodiments, the width 650 is approximately84 mm. The battery pack 18B defines a height 654 within a range ofapproximately 50 mm to approximately 65 mm. In some embodiments, theheight 654 is approximately 58.27 mm. The volume of the battery pack 18is between about 487,500 mm³ to about 848,250 mm³ (e.g., about 507,384mm³). The total weight of the battery pack 18B is within a range ofapproximately 1 lb. to approximately 1.5 lbs. In some embodiments, thetotal weight of the battery pack 18B is approximately 1.2 lbs. (about546 grams).

The battery pack 18B has an ACIR within a range of approximately 45milliohms to approximately 55 milliohms. The battery pack 18B has a DCIRwithin a range of approximately 59 mΩ to approximately 69 mΩ. In someembodiments, the DCIR of the battery pack 18B is about 64 mΩ.

In comparison, an existing battery pack has a length of about 130 mm, awidth of about 79 mm, and a height of about 86.5 mm. Such a battery packhas a weight of about 2.4 lbs.

Due to the higher number of cells used in the battery pack 18, thebattery pack 18 may be more vulnerable to damage. The battery pack 18includes a C-shaped channel 658 to reinforce the terminal block 466. Theillustrated channel 658 is formed by a metal stamping. FIGS. 74-75illustrate the C-shaped channel 658. As shown in FIG. 74, the C-shapedchannel 658 includes a front ledge 662 and two C-shaped bars 664connected to the front ledge 662.

FIG. 75 illustrates positioning of the C-shaped channel 658 within thebattery pack 18. The C-shaped channel 658 is positioned around theterminal block 466 of the battery pack 18. The front ledge 662 ispositioned in front of the terminal block 466 supporting a portion ofthe top housing of the battery pack 18. The C-shaped bars 664 areprovided on the sides of the terminal block 466 supporting the rails ofthe top housing that receive the corresponding portion of the power tool10. In some embodiments, an L-shaped channel 660 (as shown in FIG. 76)rather than the C-shaped channel 658 may be used.

FIG. 79 illustrates the terminal block 466 of the battery pack 18. Theterminal block 466 includes power terminals, a charger terminal and oneor more (e.g., two) communication terminals (collectively referred to asbattery pack terminals 482).

The battery pack terminals 482 may be made from an EFTEC copper alloymaterial or FAS 680 copper alloy material. In the illustratedconstruction, the charger terminals and the communication terminals areshorter than the power terminals, which may allow more space for othercomponents (e.g., circuitry for charging) of the battery pack 18. Therelatively longer power terminals also ensure connection is maintainedduring operation to inhibit arcing, etc.

With reference to FIGS. 80-81, a motor assembly 1140 is shown includinga motor housing 1145, a motor 1115 positioned within the motor housing1145, and a PCB assembly 1155 coupled to an end of the motor housing1145 opposite the end from which a motor shaft 1151 protrudes. The PCBassembly 1155 includes a heat sink 1160, a power PCB 1165 disposed on arear side of the heat sink 1160, and a position sensor PCB 1355 disposedon an opposite side of the heat sink 1160. The motor 1115 also includesa permanent ring magnet 1305 mounted on the rear of the rotor shaft1151. The ring magnet 1305 is affixed to the rotor shaft 1151 andco-rotates with the rotor shaft 1151, emanating a rotating magneticfield that is detectable by Hall-effect sensors 1120 (FIG. 81) mountedon the position sensor PCB 1355. In other words, the Hall-effect sensors1120 on the position sensor PCB 1355 detect the rotating magnetic fieldemanated by the ring magnet 1305. In some embodiments, the positionsensor PCB 355 is at least partially covered by a low-pressure molding.

The Hall-effect sensors 1120 output motor feedback information, such asan indication (e.g., a pulse) when the Hall-effect sensors detect a poleof a magnet 1305 attached to a rotating shaft 1151 of the motor 1115.Based on the motor feedback information from the Hall-effect sensors1120, the motor controller may determine the rotational position,velocity, and/or acceleration of the shaft 1151. In the illustratedembodiment, there are three Hall-effect sensors 1120 on the positionsensor PCB 1355. Alternatively, there may be other numbers ofHall-effect sensors 1120 (e.g., two, four, etc.).

With reference to FIG. 82-84, an end cap 1205 is shown with contactplates 1275 a, 1275 b, and 1275 c (also referred interchangeably hereinas coil contact plates 1275) that short-circuit diagonally oppositepairs of coil windings. The coil contact plates 1275 are generallysemi-circular in shape and staggered to avoid contact between adjacentcoil contact plates 1275. In particular, the first coil contact plate1275 a is positioned radially inward of the second coil contact plate1275 b, and the first coil contact plate 1275 a is positioned radiallyoutward of the third coil contact plate 1275 c. Each of the coil contactplates 1275 includes a first terminal 1280 and a second terminal 1285diagonally opposite the first terminal 1280. Stator windings areconnected to hooks 1290 on the respective terminals 1280, 1285.

With continued reference to FIGS. 83 and 84, a plurality of spacers 1293are coupled to the coil contact plates 1275. At least some of thespacers 1293 are positioned between adjacent coil contact plates 1275 inorder to create and maintain an insulating gap (e.g., a space) betweenthe adjacent coil contact plates 1275. In some embodiments, theplurality of spacers 1293 are equally spaced circumferentially aroundthe coil contact plates 1275. The spacers 1293 are pre-molded onto thecoil contact plates 1275 before the coil contact plates 1275 areovermolded. As such, the coil contact plates 1275 and the spacers 1283are overmolded in the end cap 1205. In particular, each of the spacers1293 are molded on one of the coil contact plates 1275. In theillustrated embodiment, the spacers 1293 include a first spacerpositioned between the first and second adjacent coil contact plates1275 a, 1275 b, and a second spacer 1293 positioned between the adjacentfirst and third coil contact plates 1275 a, 1275 c. As such, insulatinggaps are created between the adjacent coil contact plates 1275. Thepre-molded spacers 1293 prevent internal shorts between coil contactplates 1275 and portions of the coil contact plates 1275 being exposed.In other words, the relative spacing between adjacent coil contactplates 1275 may be difficult to adequately control during an injectionmolding process, and the coil contact plates 1275 may deform during themolding process from the injection pressure. This deformation of thecoil contact plates 1275 can cause internal shorts or exposure. Byadding the pre-molding spacers 1293, deformation of the coil contactplates 1275 while being overmolded is prevented.

Thus, the invention may provide, among other things, high-power,battery-powered electrical system, such as a power tool system.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe scope and spirit of one or more independent aspects of the inventionas described.

One or more independent features and/or independent advantages of theinvention may be set forth in the claims.

What is claimed is:
 1. An electrical combination comprising: anelectrical device including a device housing, a load supported by thedevice housing, the load being operable to output at least about 1800watts (W), and a device terminal electrically connected to the load; abattery pack including a pack housing, battery cells supported by thepack housing, the battery cells being electrically connected and havinga nominal voltage of up to about 20 volts, and a pack terminalelectrically connectable to the device terminal to transfer currentbetween the battery pack and the electrical device; and a controlleroperable to control the transfer of current.
 2. The combination of claim1, wherein the load is operable to output at least about 2200 W.
 3. Thecombination of claim 1, wherein the load includes a motor including anoutput shaft, the motor being operable to output at least about 1800 W.4. The combination of claim 3, wherein the motor includes a brushlessdirect current motor.
 5. The combination of claim 4, further comprisinga power circuit electrically connected between the battery cells and themotor, the power circuit including semi-conducting switches operable toapply current across windings of the motor.
 6. The combination of claim5, further comprising a heat sink in heat transfer relationship with theswitches, the heat sink being intersected by a rotational axis of arotor of the motor.
 7. The combination of claim 6, wherein a combinedlength of the motor and the heat sink is up to about 84 mm.
 8. Thecombination of claim 3, wherein the motor includes a stator having anominal outer diameter of between about 60 millimeters (mm) and about 80mm.
 9. The combination of claim 1, wherein the battery cells each have adiameter of between about 18 mm and about 21 mm and a length of betweenabout 65 mm and about 71 mm.
 10. The combination of claim 1, wherein thebattery pack includes up to 15 battery cells.
 11. The combination ofclaim 1, wherein the device includes a tool, and wherein the loadincludes a motor including an output shaft, the motor being operable todrive a tool member.
 12. The combination of claim 11, wherein the toolincludes a hand-held tool, and wherein the pack housing is connectableto and supportable by the device housing such that the battery pack issupportable by the hand-held tool.
 13. The combination of claim 1,wherein the load includes a motor, and wherein control electronicsincluding the controller have a volume of up to about 15,000 cubicmillimeters (mm³), the motor has a volume of up to about 92,000 mm³, andthe battery pack has a volume of up to about 1,534,500 mm³.
 14. Thecombination of claim 1, wherein the load includes a motor, and whereincontrol electronics including the controller have a weight of up toabout 19.6 grams (g), the motor has a weight of up to about 1.89 pounds(lbs.), and the battery pack has a weight of up to about 3.5 lbs.
 15. Amethod of operating an electric motor, the method comprising: supplyinga first voltage signal at a first duty cycle through a switch to themotor; determining whether a current to be supplied to the motor exceedsa threshold associated with the switch; and in response to the currentto be supplied exceeding a threshold, supplying a second voltage signalat a second duty cycle to the motor, the second duty cycle being lessthan the first duty cycle.
 16. The method of claim 15, furthercomprising: after supplying a second voltage signal at a second dutycycle to the motor, determining whether a current to be supplied to themotor exceeds the threshold; and in response to the current to besupplied exceeding the threshold, supplying a third voltage signal at athird duty cycle to the motor, the third duty cycle being less than thesecond duty cycle.
 17. The method of claim 16, further comprising: aftersupplying a second voltage signal at a second duty cycle to the motor,determining whether a current to be supplied to the motor exceeds thethreshold; and when the current to be supplied does not exceed thethreshold, supplying the first voltage signal at the first duty cycle tothe motor.
 18. An electric motor comprising: a stator including a coredefining a plurality of teeth, a plurality of coils disposed onrespective stator teeth, and an end cap proximate an end of the core,the end cap including a plurality of coil contact plates molded in theend cap and a first terminal and a second terminal separate from andconnectable to the contact plates, the contact plates short-circuitingopposite ones of the plurality of coils; and a rotor supported forrotation relative to the stator.
 19. The motor of claim 18, wherein eachcontact plate has a thickness of no more than about 1 mm, and whereineach terminal has a thickness of at least about 1.3 mm.
 20. The motor ofclaim 18, wherein the end cap includes a pre-molded annular carrierdefining a circumferential groove in a side facing the stator, the coilcontact plates being supported in the groove, a plurality of spacers inthe groove, an air gap between adjacent coil contact plates beingmaintained by the spacers, and a resin layer injection molded over thecarrier and the supported coil contact plates.